The invention relates to generating and displaying a panoramic view of a jaw from a tomographic imaging dataset. The invention has particular application to viewing the maxilla, the mandible, or both in a dataset of part of the head of a human or other mammal.
In certain forms of dental medicine and surgery, a “panoramic” image of the jaw is used to examine the jaw, for example, for monitoring of dental health and condition, diagnosis, and planning of prosthetic and other surgical procedures. The panoramic image of the jaw, like a panoramic photograph, depicts the jaw as if it were imaged onto an imaginary approximately cylindrical sheet with the axis of the sheet upright, and the sheet were then unrolled into a flat form.
A set of three-dimensional data relating to a property of an object that varies over space within the object may be obtained in various ways. For example, an x-ray image of a target may be obtained by placing the target between a source of x-rays and a detector of the x-rays. In a computed tomography (CT) system, a series of x-ray images of a target are taken with the direction from the source to the detector differently oriented relative to the target. From these images, a three-dimensional representation of the density of x-ray absorbing material in the target may be reconstructed. Other methods of generating a three-dimensional dataset are known, including magnetic resonance imaging, or may be developed hereafter.
From the three-dimensional data, a desired section or “slice” may be generated, including a curved slice. For example, a slice curving along the jaw, corresponding to a panoramic view of the jaw may be generated, provided that the position of the jaw within the three-dimensional dataset is known. However, the jaws are not of uniform thickness, but tend to be narrower at the toothed edges, the top of the mandible and the bottom of the maxilla, and broaden away from those edges. A conventional tomographically synthesized panoramic view uses a slice of constant thickness, and thus tends to include too much of the mouth near the toothed edges of the jaws and too little away of the mouth from those edges.
There is therefore a hitherto unfulfilled need for a better panoramic view of the mandible or maxilla that can be reliably automatically generated.